The application of methods for retroviral mediated gene transfer and hepatocellular cultivation to hepatic gene therapy requires large scale production of retroviruses and large scale cultivation of hepatocytes. The "Virus and Tissue Culture Core" is designed to provide retroviruses, to provide facilities for large scale preparation of hepatocytes, and provide hepatocyte feeder stocks and cultures is association with the experiments of the investigators. Each of the investigators participating in this program project grant will make use of retroviruses and each investigator will make use of hepatocyte cultures. This core play a particularly active role in the procurement as well as the harvesting of human liver samples which will be used by several investigators on this project.